Optimal cell viability during patient transfusion is one of the main hurdles facing cell therapy.
Last week, Ian Copland and colleagues at Emory University published a fascinating paper in Stem Cell Reports about the biological availability of mesenchymal stem cells following cryopreservation with DMSO. The authors reported that MSCs thawed after being cryopreserved with DMSO showed a 60% reduction in cytoskeletal actin, a globulal protein critically responsible for cell mobility. The importance of the findings was once again emphasized when the authors concluded that cryopreserved MSCs are distinct, and appear weaker, than fresh, live MSCs in terms of their bioavailability following transfusion.
In another recent manuscript, published by Mohapatra and colleagues, transfusion was again used as an example where a low concentration of DMSO is preferred. The authors found that while a concentration of 10% DMSO gave the highest viability of hematopoietic stem cells post-thaw (93%), a concentration of 2% DMSO, with the addition of trehalose or sucrose, was the preferred strategy to adopt for therapy.
These are just two of the many examples illustrating the complexity of the subject. The topic of cryoprotectant toxicity is indeed a controversial one, and one that sits at the heart of development of cell therapies. Strategies to either reduce or completely eliminate toxicity have been extensively researched, yet an optimal approach is still a controversial subject.
While some papers, such as that by Ali Eroglu’s lab at Georgia Health Sciences University, published in PLoS One in 2011, which investigated the effect of toxicity of penetrating cryoprotectants, have attempted to shed some light on the biochemical effect of cryoprotectants on the cryosurvival of cells, in this case oocytes, other approaches have focused on developing novel methodologies and formulations by completely moving away from standard cryoprotectants such as DMSO. New approaches, such as magnetic cryopreservation, a system employing magnetic field-programmed freezers called “Cells Alive System”, have tried to develop completely DMSO-free cryopreservation strategies.
It is clear that developing a comprehensive and robust cryopreservation strategy for direct patient use is a multi-pronged approach that requires consideration of multiple aspects of the cell preparation cascade. From obtaining cells, through to cryopreservation, transport and thawing such cells for use, this problem requires a multidisciplinary approach.
Some are taking a mathematical approach to solving such problems. Bayesian statistics were used in a recent paper published in Quantitative Methods, which investigated the compounded effect of a number of factors, including cooling rate and temperature, composition of cryoprotectant and additives as well as loading procedure to develop an optimized procedure for cryopreservation of cells.
In 2010, Etienne Sokal and colleagues asked, in a paper about hepatocye cryopreservation, “Is it time to change the strategy?” – and the answer is still unclear.
Akron has long been concerned with redesigning traditional cryopreservation approaches. But as we design strategies to facilitate this difficult process, we are curious to hear from you.
What is your cryopreservation strategy, and is it working for you? Have you tried any new approaches or cryopreservation formulation? Are you curious about trying out a new technology but have too many questions?
We would love to hear from you. Join the conversation by posting a comment to this article. To reward your feedback, we will be gifting a free Akron t-shirt to every person that comments on this this topic, so don’t forget to leave your email address. A free t-shirt for sharing your experience? It’s a no brainer.
MEET AKRON ONE-ON-ONE AT ISSCR IN VANCOUVER
Check out our blog next week for another opportunity to receive a free Akron t-shirt and details about meeting us at ISSCR in Vancouver, where we will be from June 18-June 21. To set up an individual meeting, contact us .